Rebuild a jonsered 670?

[SPH]

Hi guys

I brought 4 bitsa saws the other week, a husky 61 that's already been sorted out, 2 670's with bits missing and an 820 that's missing tons.
The 61 was the main reason for buying the lot and it's worked out fine. One of the 670's has most of its parts but no compression, the other is just a bottom end and tank handle.
The 820 is missing both side covers, has no compression and no spark. I don't think I'll bother with that one.

I pulled the jug off the main saw and the ring was bound up in the piston. I thought there might be some hope for it when I freed up the ring but no, still stuff all compression. If I take some pics of the jug can I get a few opinions on its condition? There seem to be pistons available for these saws so it'd be an easy fix.

I have both side covers but no chain break band or handle.

I've pulled the coil and checked all the connections but still can't get a spark, a new coil is in order I guess. It's a one part ignition so that should be fairly straight forward.

I'll take some pictures in the morning and see what everyone thinks.

 

[Agrarian]

I've pulled the coil and checked all the connections but still can't get a spark, a new coil is in order I guess. It's a one part ignition so that should be fairly straight forward.

Did you pull the wire off the coil that goes to the kill switch when you tested it? Sometimes these can get shorted and act like the switch was OFF.
Did you test it with a known good spark plug?
How fast was the flywheel spinning when you tested it? Many saws will not produce a spark unless the flywheel is moving fairly fast.

 

[SPH]

Plug was off my running 61, switch was disconnected, yanked on the pull cord.
The only thing I can't check is the plug lead.

 

[Flat47]

Keys on the crank shaft can shear but give you just enough friction to spin the whole assembly. Been there, done that. I saved my 266 by prying out the piston ring, dressing the ring groove with emery cloth and putting in a new ring.
Sent you a pm about that 820.

 

[merr6267]

A new ring for that 670 can be had for about $6. Same as 372xp and others. I am dealing with one that was in similar condition to yours. It's run well, and died, but I think I have it licked at this point, but it's a leaky intake boot, and I'm having difficulty finding a replacement.

I have not run it against my 372, but it is a great runner.

 

[SPH]

Ordered a ring and a new coil. All of $35 delivered. I guess we'll all get to find out how it goes!